The invention generally relates to an integrated sensor system for monitoring a combustion process or combustion chamber conditions inside an engine cylinder. In particular, the invention relates to an integrated sensor system for monitoring a combustion process or combustion chamber conditions using a light communication channel and a sensor embedded in a cylinder head gasket of an engine.
An engine may encounter several combustion-related problems that can prevent it from running optimally. For example, the air and fuel mixture may be incorrect, or there may be contaminants in the air and fuel mixture. Engine problems may also arise when compression does not occur properly because the valves are not sealed tightly, the air and fuel mixture leaks past the piston during the compression stroke, or a gap forms between the cylinder and the cylinder head due to wear.
The cylinder head of an engine provides a number of functions such as sealing the top of the cylinders, providing a mounting for valve train components, providing guides and ports for the intake and exhaust valves, or providing the spark plugs access to the combustion chamber. Each recessed area above the piston in the cylinder head is a combustion chamber in which the air and fuel mixture burns. The intake of air and fuel mixture and the exit of combustion gases must be regulated to allow the engine to operate properly.
The cylinder head must be sealed tightly to contain the high pressure resulting from the combustion process. The cylinder head gasket, which is placed between the cylinder head and the engine block, functions to form the seal. Because of the severe environment in the engine""s cylinder head, the components around the cylinder head must be able to withstand severe conditions such as temperatures that may vary from xe2x88x9240xc2x0 C. to +250xc2x0 C. The cylinder head gasket are also subjected to very high pressures. Monitoring or measuring in-cylinder parameters, particularly those relating to engine combustion, would facilitate the optimization of an engine""s performance.
Strain gages can be used to measure or monitor changes in the gas mixture composition, pressure, or temperature in the combustion chamber. Various types of strain gages exist, but they generally convert mechanical motion into an electrical signal. In choosing the type of strain gage material to use, one has to consider material characteristics such as temperature sensitivity, stability, and resistance.
Traditional wired strain gages are usually difficult to assemble and are less reliable due to the number of wires involved. Signals passing through wires often cause cross talking and interference with the signal transmission in adjacent wires. Signals passing through wires also cause electromagnetic interference in adjacent wires unless some type of shielding is used. These factors cause signal distortion.
While optical fibers are sometimes used in place of wires or incorporated in a molded structure, optical fibers increase the cost of the electronic component system. Additionally, the integration of optical and electrical components is usually not suited for high volume manufacturing because of difficulties in assembly.
The various embodiments of the invention utilize light channel technology that is connected to a sensor embedded in a cylinder head gasket. The invention provides means by which in-cylinder conditions such as gas mixture or charge composition can be monitored efficiently in real-time. In addition, the integration of various components according to the invention, in which one of the components is preferably a powertrain system, provides several benefits in terms of cost, weight, complexity, signal noise, reliability, space, and the so-called noise, vibration, and harshness (NVH) of the integrated system.
Integration in an engine cylinder head gasket of a sensor such as those for combustion composition, pressure, or temperature monitoring is achieved using novel light channel technology herein referred to as light communication channel (LCC) technology. One end of the LCC may be fabricated as part of other engine structures, such as a plastic intake manifold, and/or connected to other structures or components such as optical detectors, powertrain system, or other process control electronics.
In one aspect of the invention, an integrated engine combustion monitoring system is provided which comprises one or more structures comprising an LCC. A sensor, which is embedded in a cylinder head gasket near a cylinder wall, is connected to the one or more structures comprising an LCC. An electronic system receives and processes a signal received by the sensor, wherein the signal received by the sensor propagates through the LCC.
In another aspect of the invention, an integrated engine combustion monitoring system is provided comprising a sensor embedded in a cylinder head gasket that includes an optical window. An LCC comprises a polymer and is directly or indirectly connected to the optical window that has a tapered, optic bundle, or a ring configuration. An electronic system receives and processes a signal received by the sensor which is positioned near a cylinder wall. The signal received by the sensor propagates through the optical window and the LCC.
The present invention is also directed to an integrated engine combustion monitoring system comprising one or more structures comprising an LCC. The one or more structures comprising an LCC are positioned between the electronic system and a sensor. The sensor is embedded in a cylinder head gasket and connected to the one or more structures comprising an LCC. The sensor, which includes an IR window that has a tapered, optic bundle, or a ring configuration, detects infrared signals arising from combustion processes that occur in a combustion chamber. An electronic system receives and processes a signal received by the sensor.
The invention enables extremely high real-time data acquisition, efficient packaging and integration, low system complexity, and lower overall cost compared to traditional combustion sensing methods that use higher-cost sensors with complex integration that includes spark plugs, fuel injectors, or dedicated probes for each combustion chamber.